refactor(core): introduce NgModule.schemas

This allows Angular to error on unknown properties,
allowing applications that don’t use custom elements
to get better error reporting.

Part of #10043

BREAKING CHANGE:
- By default, Angular will error during parsing
  on unknown properties,
  even if they are on elements with a `-` in their name
  (aka custom elements). If you application is using
  custom elements, fill the new parameter `@NgModule.schemas`
  with the value `[CUSTOM_ELEMENTS_SCHEMA]`.

  E.g. for bootstrap:
  ```
  bootstrap(MyComponent, {schemas: [CUSTOM_ELEMENTS_SCHEMA]});
  ```

modules/@angular/platform-browser/test/browser/bootstrap_spec.ts

@@ -8,7 +8,7 @@
 
 import {LowerCasePipe, NgIf} from '@angular/common';
 import {XHR} from '@angular/compiler';
-import {APP_INITIALIZER, Component, Directive, ExceptionHandler, Inject, Input, NgModule, OnDestroy, PLATFORM_DIRECTIVES, PLATFORM_INITIALIZER, PLATFORM_PIPES, Pipe, ReflectiveInjector, bootstrapModule, createPlatformFactory, provide} from '@angular/core';
+import {APP_INITIALIZER, createPlatformFactory, CUSTOM_ELEMENTS_SCHEMA, Component, Directive, ExceptionHandler, Inject, Input, NgModule, OnDestroy, PLATFORM_DIRECTIVES, PLATFORM_INITIALIZER, PLATFORM_PIPES, Pipe, ReflectiveInjector, bootstrapModule, createPlatform, provide} from '@angular/core';
 import {ApplicationRef, disposePlatform} from '@angular/core/src/application_ref';
 import {Console} from '@angular/core/src/console';
 import {ComponentRef} from '@angular/core/src/linker/component_factory';
@@ -94,6 +94,10 @@ class HelloCmpUsingPlatformDirectiveAndPipe {
   show: boolean = false;
 }
 
+@Component({selector: 'hello-app', template: '<some-el [someProp]="true">hello world!</some-el>'})
+class HelloCmpUsingCustomElement {
+}
+
 class _ArrayLogger {
   res: any[] = [];
   log(s: any): void { this.res.push(s); }
@@ -331,5 +335,15 @@ export function main() {
          });
        }));
 
+    it('should allow to pass schemas', inject([AsyncTestCompleter], (async: AsyncTestCompleter) => {
+         bootstrap(HelloCmpUsingCustomElement, {
+           providers: testProviders,
+           schemas: [CUSTOM_ELEMENTS_SCHEMA]
+         }).then((compRef) => {
+           expect(el).toHaveText('hello world!');
+           async.done();
+         });
+       }));
+
   });
 }